You now really have no excuse; a review of research finds that strength training improves strength and the performance of daily activities in older adults. That's the word from the Cochrane Collaboration, which publishes evidence-based reviews in the Cochrane Library.
Progressive resistance training—training that increases the weight or resistance as you improve—not only strengthens older people but improves their ability to perform activities like walking, climbing steps, and even taking a bath or making dinner, says the review. It also appears to reduce pain from arthritis. The authors' one caveat: The 121 trials whose data they analyzed did not give enough evidence to assess the risks of strength training or the effects over the long term.